Niacinamide for aging and pigmentation (review, 2021)

A single-author review of how niacinamide works and what trials show. It concludes that topical niacinamide reduces the progression of skin aging and pigmentation and is well tolerated. The author is unusually direct about the limits, writing that there is still no convincing evidence niacinamide has specific molecular targets for these effects. In other words the ingredient works in practice more clearly than the explanation for why does.